1. Technical Field
The present invention relates in general to communication services, and, in particular, to a system, method, and program for providing communication services in a wireless network. Still more particularly, the present invention relates to a system, method, and program for controlling access to and invocation of data services in a wireless network.
2. Description of the Related Art
Over the last several years, wireless or mobile communication has proliferated throughout the world, and usage of digital and cellular services for voice and data communication has been on the rise. The popularity of wireless communication services has driven communication service providers to develop and provide various new services and features for their subscribers.
One such service is pre-paid wireless communication service for voice or data. To obtain pre-paid services, a subscriber purchases communication services in advance of use. Following payment, the service provider permits the subscriber to utilize communication services and electronically tracks subscriber usage (e.g., by time or data throughput) to maintain a running balance in the subscriber""s account. If the balance reaches zero (or other predefined threshold), the service provider terminates the subscriber""s access to the communication services until the subscriber pre-pays for additional communication services.
With reference now to FIG. 1, a block diagram of a conventional Generalized Packet Radio Service (GPRS) wireless communication system 100 that provides pre-paid data services to a subscriber of pre-paid data services is shown. Wireless communication system 100 includes a subscriber unit 102 and an access system 105, which provides subscriber unit 102 with access to public switched telephone network (PSTN) 118 and data network 120. Access system 105 includes a base station system (BSS) 104, a mobile switching center (MSC) 106, a home location register (HLR) 110, a service control point (SCP) 112, at least one serving GPRS support node (SGSN) 114, and at least one gateway GPRS support node (GGSN) 116. MSC 106 controls access to voice communication services by subscriber unit 102, and SGSN 114 and GGSN 116 control access to data communication services by subscriber unit 102. While GGSN 116 may be in the subscriber""s home network or a visited network, the HLR 110 and SCP 112 that interact with SGSN 114 to provide subscriber unit 102 with access to pre-paid data services are always located in the subscriber""s home network, as indicated by dashed line illustration. Although the subscriber""s home network will also likely include an MSC, BSS, and SGSN, the BSS, MSC, and SGSN involved in providing the subscriber with access to pre-paid data services belong to the network in which subscriber unit 102 is physically located, and therefore may or may not be in the subscriber""s home network depending upon whether the subscriber is roaming.
To obtain communication services, subscriber unit 102 first initiates communication with access system 100 by performing an attach procedure initiated by turning on subscriber unit 102. In response to subscriber unit 102 attaching, SGSN 114 queries HLR 110 to obtain the subscriber""s profile, which identifies services and features available to the subscriber. Subscriber unit 102 then sends to BSS 104 a request to establish data communication with data network 120. BSS 104 in turn forwards the request to SGSN 114, which utilizes the previously obtained subscriber profile to determine whether or not to enable the requested access. If required, SGSN 114 queries SCP 112 regarding whether or not to enable subscriber unit 102 to access pre-paid data services. In response to this query, SCP 112 determines whether or not the subscriber has subscribed to pre-paid data services and has a sufficient account balance to permit access. SCP 112 then sends a reply to SGSN 114 in answer to the query. If SGSN 114 receives a negative reply from SCP 112, then SGSN 114 denies access to pre-paid data services by subscriber unit 102. However, if SGSN 114 receives a positive reply from SCP 112, then SGSN 114 continues setting up the requested session and forwards the request for data services to GGSN 116. During a session in which pre-paid data services are utilized by subscriber unit 102, SGSN 114 informs SCP 112, via a query, after a unit of services has been utilized. SCP 112 processes such queries to track the services utilized by subscriber unit 102 and responds to each query with a reply indicating whether the remaining account balance for subscriber unit 102 is sufficient to allow continued access. If so, SGSN 114 permits the data session to continue. If, on the other hand, the reply from SCP 112 indicates that the subscriber""s account balance is too low, SGSN 114 terminates the data session. Thus, SCP 112 controls the data communication session between subscriber unit 102 and data network 220.
The conventional access paradigm for data services illustrated in FIG. 1 is subject to a number of drawbacks recognized by the present invention. First, even though a subscriber has subscribed to pre-paid or other data services in his home network, the subscriber may not be able to access such data services when roaming. This problem arises because, in order for the SGSN 114 of a visited network to inter-operate with the home network""s SCP 112 to regulate access to data services, the visited network""s SGSN 114 must be configured with appropriate software for each data service. Thus, if the SGSN 114 of the visited network in which subscriber unit 102 is roaming is not configured with the appropriate software, then requested data services cannot be provided to subscriber unit 102. As a result, the ability of subscribers to data services to roam is restricted by the software configurations of the SGSNs 114 with which subscriber unit 102 communicates.
Second, the conventional access paradigm for data services is inefficient in terms of the number of messages (queries and replies) required to support a data session. As subscriber unit 102 is moved within a wireless network, the data session may be handed off between BSSs 204 and SGSNs 114. Because the SGSN 114 is required to regulate access to data services under control of SCP 112, when a handoff occurs the SGSN 114 receiving the handoff must query SCP 112 and receive a reply from SCP 112 in order to obtain state for the data session. The queries and replies resulting from handoff of a data session between SGSNs 114 consume valuable network bandwidth and processing resources.
In view of the above and other disadvantages of the prior art, the present invention recognizes the need to provide an improved method and system for accessing wireless data services that reduce messaging and enable roaming subscribers to access data services.
In accordance with the present invention, a wireless communication system includes at least a service control point and a gateway system that is coupled to a data network. To obtain access to data services, a wireless subscriber unit establishes communication with a gateway system and requests data services from the gateway system. In response to the request, the gateway system queries the service control point regarding authorized data services for the subscriber unit. If the gateway system receives a negative reply from the service control point, then the gateway system denies access to the data services by the subscriber unit. However, if the gateway system receives a positive reply from the service control point, then the gateway system enables access to the data services by the subscriber unit.
In a preferred embodiment, the gateway system tracks the requested data services utilizing pre-defined resource units. In one embodiment, the gateway system tracks service utilization by periodically querying and receiving a reply from the service control point after each pre-defined resource unit has been utilized. In this embodiment, the service control point updates an account balance of remaining resource units in response to receiving the queries and informs the gateway system when data access should be denied.
The above as well as additional objects, features, and advantages of the present invention will become apparent in the following detailed written description.